Compositions useful for treating parkinsonism

ABSTRACT

Disclosed herein are compounds of the formula:   WHEREIN Ad is 1-adamantyl; R is H or CH3; X is COOM or   WHEREIN M is H or a pharmaceutically acceptable cation, and R1 is lower n-alkyl; and the pharmaceutically acceptable salts thereof. Preferred are ethyl-4-(N-(1-adamantyl)-N-methylamino) butyrate, 3-(N-(1-adamantyl-N-methylamino)propionic acid and their pharmaceutically acceptable salts. These compounds are particularly useful in the treatment of parkinsonism.

ilnited States Patent 1 1 Gold [4 1 June 24, 11975 1 QOMPOSITIONS USEFUL FOR TREATING PARKINSONISM [75] Inventor: Elijah H. Gold, West Orange, NJ.

[73] Assignee: Schering Corporation, Kenilworth,

[22] Filed: Oct. 19, 1973 [21] App]. No.: 408,021

[52] US. Cl. 260/468 G; 260/50l.1;260/501.12; 260/501.13; 260/501.17; 260/514 G; 124/305; 124/316; 124/317; 124/319 [51] Int. U. C07c 101/14 [58] Field of Search 260/468 G, 514 G [56] References Cited UNITED STATES PATENTS H1969 Daenikes ..260/563 10/1970 Smith ..260/563 Primary ExaminerRobert Gerstl Attorney, Agent, or Firm-Arthur E. Wilfond; Bruce M. Eisen; Stephen B. Coan [57] ABSTRACT Disclosed herein are compounds of the formula:

wherein Ad is l-adamantyl; R is 1-1 or CH X is COOlVl or wherein M is 1-1 or a pharmaceutically acceptable cation, and R is lower n-alkyl; and the pharmaceutically acceptable salts thereof.

7 Claims, N0 Drawings 1 (TOR/[POSITIONS USEFUL FOR TREATING PARKINSONISM This invention relates to compounds of the formula:

wherein Ad is l-adamantyl; R is H or 0H,; X is COOlVl wherein M is H or a pharmaceutically acceptable cation, and R, is lower alkyl; and the pharmaceutically acceptable salts thereof.

More specifically this invention relates to [N-( ladamantyl)-n-methylamino]lower alkaneic acid derivatives, such as 3-[N-( l-adamantyl)-N- methylamino1propionic acid, the lower nalkyl esters of 4-[ N-( l -adamantyl)-N-methylamino]butyric acid, their pharmaceutically acceptable salts and intermediates in their preparation, and to processes for using said compositions. 3-[N-( 1-adamantylamino)]Propionic acid is an intermediate in the preparation of 3-[N-( ladamantyl)'-N-methylamino]propionic acid while the lower n-alkyl ester of 4-[N-( ladamantylamino)]butyric acid is an intermediate in the preparation of the lower n-alkyl ester of 4-[N-( ladamantyl)-N-methylamino]butyric acid.

The invention, in its process of using aspect, comprises treating symptoms of parkinsonism by administering to a mammal exhibiting parkinsonism a therapeutically effective quantity of at least one of the above N-( l-adamantyl)-N-methylamino acids.

A still more specific and preferred representation of the composition of matter aspect of this invention are the chemical compositions ethyl-4-[N-(1-adamantyl)- N-methylamino]butyrate and 3-[N-(l-adamantyl)-N- methylamino1propionic acid, their pharmaceutically acceptable salts and pharmaceutical compositions thereof. Ethyl-4-[N-(l-adamantylamino)]butyrate is an intermediate in the preparation of ethyl-4-[N-(ladamantyl)-N-methylarnino]butyrate.

The compounds of the present invention may be prepared by the following reaction schemes wherein Ad l-adamantyl, Et ethyl, and R lower n-alkyl:

EtOH

EtOH

The reaction scheme D, aminoadamantane is reacted with a lower alkyl 4-chlorobutyrate and sodium bicarbonate in acetonitrile to yield the lower alkyl ester 4-[N-(l-adamantyldamino)lbutyric acid (III). This in turn is hydrogenated in reaction scheme E with formalin, a 37% aqueous formaldehyde solution, and acetic acid in the presence of palladium on charcoal to yield lower n-alkyl-4 [N-( l-adamantyl )-N- methylamino1butyrate (IV).

The lower alkyl radicals as used herein are linear, contain 1-6 carbon atoms, and include methyl, ethyl, n-propyl, n-butyl, n-amyl, and n-hexyl. Preferred is ethyl.

Exemplary of the pharmaceutically acceptable acid addition salts of the butyrate are those formed with maleic, fumaric, succinic, tartaric, citric, malic, cinnamic, sulfonic, hydrochloric, hydrobromic, sulfuric, phosphoric, and nitric acids. These salts may be prepared in the conventional manner by treating a solution or suspension of the free base in an organic solvent with the desired acid, and then recovering the salt which forms by crystallization techniques.

The propionic acid may be salified with a pharmaceutically acceptable cation. This includes any cation which forms salts of the 3-[N-( l-adamantylamino)]- propionic acid which do not create any difference in kind of pharmaceutical activity from that shown by the corresponding free acid. Such cations may be used to provide greater solubility or greater ease in formulation than the corresponding free acid. Representative of such salts are those wherein the cation is an alkali metal such as sodium or potassium, ammonium, substituted ammonium such as diethanolammonium or such metal cations as calcium or aluminum. The propionic acid may also be hydrated.

Parkinsonism is a degenerative disease of the nervous system. The disease is manifest by its three cardinal characteristics: involuntary tremors, rigidity, and akinesia. Extrapyramidal syndromes exhibited with this AdNHCH CHgCOgH condition include gait and postural abnormalities, oculargyric crisis and profuse salivation.

Attempts at treating these symptoms have involved the use of such classes of drugs as for example, antihistamines (diphenhydramin e), anticholinergics (atropine sulfate, trihexyphenidyl) and amphetamines (dextroamphetamine sulfate) with varying degrees of success. However, these drugs, due to their inherent side effects, have a somewhat limited degree of utility. For example, anticholinergics may precipitate acute glaucoma in certain individuals; antihistamines may cause drowsiness, and amphetamines and similar central nervous system (C.N.S.) stimulants are contraindicated in those patients also having cardiac conditions.

Recently the use of L-dopa and amantadine hydrochloride, a drug first used for its antiviral activity, has been introduced for treating symptoms of parkinsonism. These drugs, although promising, require high dosages and exhibit debilitating side effects which severely limit their utility. It is an object of this invention to provide a new agent with an improved therapeutic index for treating the manifestations of the disease.

In tests in rats, the compositions of this invention exhibit a greater therapeutic index (T.I.) than corre- .sponding doses of amantadine hydrochloride required to achieve a comparable response. Concomitant with l this greater therapeutic index, there is a marked decrease in the debilitating side effects which may accompany the administration of amantadine hydrochloride, e.g. nervousness, insomnia, psychic reactions and the ataxia. v

Based upon standard laboratory tests and procedures, the effective dosage of the active ingredient of the compositions of this invention is considered to be within the range of from about 0.3 to 6 mg. per kg. of mammalian body weight per day. For ethyl-4-[N-(1- adamantyl)-N-methylamino]butyrate the dosage range can be between about 50 to 400 70 per 70nkg. per day. While for 3-[N-( l-adamantyl)-N- methylamino1propionic acid the dosage range can be between 25 to 200 mg. per 70 kg. per day. The daily dosage is preferably administered in divided doses. The exact dosage administered will of course be dependent upon the age, weight, and progression of the disease in the recipient.

The compounds of. this invention may be administered alone or combined with other medicaments. In any event, a suitable pharmaceutically acceptable car'- rieris generally employed. A carrier is selected according to the route of administration to be used, i.e., orally or parenterally, as well as according to the physical properties of the compounds and standard pharmaceutical practice. The oral route is preferred. The carrier should not react chemically with the compound to be administered. The preparations containing the active ingredients of this invention may be in the form of tablets, capsules, syrups, elixirs, suspensions, suppositories and the like. In the formulations of pharmaceutical preparations there can be employed such pharmaceutically acceptable diluents as for example, water, gelatin, lactose, starches, magnesium stearate, talc, vegetable oils, gums and theobroma oil.

The invention will be described in greater detail with respect to the. following illustrative, but non-limiting examples:

EXAMPLE 1 3-[N-( l-adamantylamino)]Propionic acid A. Method A Reflux a mixture of 117.76 g. (0.78 moles) of laminoadamantane, also called amantadine, and 78.0 g. (0.78 moles) of ethyl acrylate in 750 ml. of ethanol for one week. Filter off the analytically pure product, m.p. 208-209C.

B. Method B Reflux a mixture of 45.3 g. (0.3 moles) of laminoadamantane and 21.6 g. (0.3 moles) of acrylic acid in 600 ml. of dry pyridine for 3 hours and then let the mixture stand at room temperature overnight. Remove the solvent in vacuo, stir the residue with 300 ml. of acetone and filter off the solids. Sublime the filter cake at C (0.1 mm.) to give the analytically pure product.

EXAMPLE 2 Ethyl-4-[ N-( l -adamantylamino butyrate Reflux a mixture of 24.02 g. (0.16 moles) of ethyl 4- chlorobutyrate, 25.7 g. (0.17 moles) of laminoadamantane and 40.0 g. (0.48 moles) of sodium bicarbonate in 250 ml. of acetonitrile with adequate stirring for about 1 week. Cool the mixture to room temperature; pour it into 1.4 liters of icewater; extract with ether; dry over anhydrous sodium sulfate; filter; evaporate the filtrate and distill the residue, collecting the fraction boiling at ll3ll6C (0.05 mm.). Dissolve this fraction, which is the free base, in ether and acidify with 5.24 M ethereal hydrogen chloride; filter off the resulting solid and crystallize it from methanolethyl acetate to give'the analytically pure hydrochloride salt of the product of this example, mp. 22 l .0222.0C (decomp).

EXAMPLE 3 3[N-( l-adamantyl)-N-methylamino]-pr0pionic acid Hydrogenate a mixture of 5.575 g. (0.0250 moles) of 3-[N-( l-adamantylamin0)l-Propionic acid, 4.05 g. (0.050 moles) of 37% aqueous formaldehyde (formalin) and 50 ml. of ethanol in the presence of 0.07 g. of 20% palladium hydroxide on carbon (Pearlman catalyst) at 53 psi for 17 days. Filter, concentrate the filtrate in vacuo at 50C, azeotropically remove the residual solvent with benzene and triturate the residue with ether to give the analytically pure product of this example, m.p.=l47.0l49.0C (dec.).

' EXAMPLE 4 Ethyl 4-[N-( l-adamantyl)-N-methylamino]butyrate Hydrogenate a mixture of 11.1 g. (0.042 moles) of ethyl 4-[N-(1-adamantyl)amino]butyrate, 6.8 g. (0.084 moles) of 37% formalin and 150 ml. of acetic acid in the presence of 0.5 g. of 5% palladium on carbon at 60 psi for 2 days. Filter, pour the filtrate into 500 ml. of icewater, basify with 65 g. of 50% sodium hydroxide followed by 25 ml. of 10% sodium carbonate, saturate with sodium chloride, extract into ether, dry over anhydrous sodium sulfate, filter and acidify the filtrate, which is the free base (b.p. l35-l36C (0.1 mm)) with a solution of 8.5 ml. of 5.24 M ethereal hydrogen chloride. Filter off the resulting solid and crystallize it from ethyl acetate to give the analytically pure hydrochloride salt of the product of this example, m.p. 206.5207.5C (decomp)v EXAMPLE 5 Formulations The following illustrate typical tablet and capsule formulations incorporating the compositions of this invention.

I. Tablet Formulations Formula and Method of Manufacture for ethyl-4 l-adamantyl)-4-methyl-amino]butyrate Coated Tablets: mg. core methylamino1butyrate hydrochloride with the lactose, dicalcium phosphate, and sodium lauryl sulfate. Screen the above mixture through a No. 60 screen and granulate with an aqueous solution containing polyvinylpyrrolidone. Add additional water, if necessary to bring powders to a pasty mass. Add corn starch and continue mixing until uniform granules are formed. Pass through .a No. screen, tray and dry in oven at 100C for 12 to 14 hours. Reduce the dried granulation through a No. 16 screen, add sodium lauryl sulfate and mgnesium stearate, mix and compress into desired shape on a tablet machine.

Coating ll. Capsule Formulations Fonnula: mg. lcapsule 3-[N-( l-adamantyl)-N-methylaminol 4 propionic acid hydrate Sodium Lauryl Sulfate 2O Lactose 150 Magnesium Stearate 76 Procedure:

Mix together 3-[N-( l-adamantyl)-N- methylamino]propionic acid, lauryl sulfate and lactose. Pass through a No. screen. Add magnesium stearate, mix and encapsulate into the proper size two-piece gelatin capsule.

Ill. Suppository Formulations Formula: m.g./2gm.

Ethyl-4-[N-( l-adamantyl)-N-methylamino] 8 butyrate hydrochloride Theobroma Oil, Pharm. Grade to make 2 gms.

Procedure:

Prepare a slurry of ethyl-4-[N-( l-adamantyl)-N- methylamino]butyrate hydrocloride with a portion of melted theobroma oil to bring the batch to final weight. Pour the melted mix, while maintaining uniformity, into approximately prepared molds and allow to cool.

Variations of the above compositions of matter and processes for the manufacture will be apparent to one skilled in the art within the spirit of the present inven tion.

I claim:

1. Compounds of the formula:

wherein Ad is l-adamantyl; R is H or CH X is COOM wherein M is H or a pharmaceutically acceptable acid addition cation, and R is lower n-alkyl; and the pharmaceutically acceptable salts thereof.

2. The compound of claim l, which is 3-[N-( ladamantylamino)]propionic acid.

3. The compound of claim 1, which is 3-[N-( l adamantyl)-N-methylaminolpropionic acid.

4. The compound of claim l, which is ethyl-4-[N-( ladamantylamino)]butyrate.

5. A compound of claim l, which is the lower n alkyl ester of 4-[N-( l-adamantyl)methylamino]butyric acid.

6. The compound of claim 5, which is ethyl-4-[N-( ladamantyl)-N-methylaminolbutyrate.

7. The compound of claim 1 which is ethyl-4[N-( 1- adamantyl )-N-methylamino]butyrate hydrochloridie. 

1. COMPOUNDS OF THE FORMULA:
 2. The compound of claim 1, which is 3-(N-(1-adamantylamino))propionic acid.
 3. The compound of claim 1, which is 3-(N-(1-adamantyl)-N-methylamino)propionic acid.
 4. The compound of claim 1, which is ethyl-4-(N-(1-adamantylamino))butyrate.
 5. A compound of claim 1, which is the lower n alkyl ester of 4-(N-(1-adamantyl)methylamino)butyric acid.
 6. The compound of claim 5, which is ethyl-4-(N-(1-adamantyl)-N-methylamino)butyrate.
 7. The compound of claim 1 , which is ethyl-4(N-(1-adamantyl )-N-methylamino)butyrate hydrochloridie. 